Sumner Redstone, the 93-year-old billionaire, is expected to step down from the Viacom board of directors following a meeting next year. Viacom set the 2017 meeting for Feb. 6 at its headquarters in Manhattan. The news comes after Redstone and his daughter Shari Redstone earlier this week cancelled plans to merge Viacom with CBS after months of back-and-forth with their fellow directors. Redstone, through his company National Amusements, is the controlling shareholder of both Viacom and CBS. He…